1 /* @(#)w_log10.c 5.1 93/09/24 */
2 /*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12 #include <LibConfig.h>
13 #include <sys/EfiCdefs.h>
14 #if defined(LIBM_SCCS) && !defined(lint)
15 __RCSID("$NetBSD: w_log2.c,v 1.1 2005/07/21 16:58:39 christos Exp $");
16 #endif
17
18 /*
19 * wrapper log2(X)
20 */
21
22 #include "math.h"
23 #include "math_private.h"
24
25
26 double
log2(double x)27 log2(double x) /* wrapper log10 */
28 {
29 #ifdef _IEEE_LIBM
30 return __ieee754_log2(x);
31 #else
32 double z;
33 z = __ieee754_log2(x);
34 if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
35 if(x<=0.0) {
36 if(x==0.0)
37 return __kernel_standard(x,x,48); /* log2(0) */
38 else
39 return __kernel_standard(x,x,49); /* log2(x<0) */
40 } else
41 return z;
42 #endif
43 }
44